Silver Hollow Nanosphere Arrays Surface-modified with Dielectric Nanoparticles to Improve the Effect of SERS and Apply for Ampicillin Detection

Abstract

The detection of residual antibiotics is of great importance nowadays Surface enhanced Raman scattering (SERS) provides a high chance in detecting trace molecules so this technique gains more attention The use of silver hollow nanosphere (HNS) arrays decorated with various dielectric nanoparticles (HfO2 TiO2 and Al2O3) using self-assembled monolayer polystyrene (PS) nanospheres as the sacrificial template is an attempt to demonstrate their potential as SERS-active substrates Silver HNS and dielectric nanoparticles (NP) were deposited by E-beam evaporation This fabrication method has the advantages of simplicity large scale production and easy size adjustment Scanning electron microscopy (SEM) images show that the hybrid structures are hexagonally arranged and Atomic force microscopy (AFM) shows that the surface morphology and the thickness of the deposited silver films are uniform The dielectric NP modified silver HNS system exhibits superior Raman scattering enhancements than silver HNS alone due to the local surface plasmon resonance (LSPR) effect which originated from the silver HNSs and metal/semiconductor interface The SERS enhancement with various dielectric materials was thoroughly compared and explained in experimental results SERS application was verified using Rhodamine 6G (R6G) as a probe molecule and the fabricated substrate was proven to be an effective SERS template for Raman signal detection Al2O3 nanoparticles decorated on silver HNS exhibited the optimized enhancement factor (EF) value which was found to be 6 2 x 107 Finally the SERS-active substrate was used for Raman detection of Ampicillin and the lowest concentration it can detect was 0 01 ppm meeting the minimum legal standards and showing that the SERS-active substrate is a promising tool for trace detection of antibiotics

Date of Award	2018 Aug 6
Original language	English
Supervisor	Jiunn-Der Liao (Supervisor)